Hard substance coatings have been applied to tools, molds, and wear parts to improve their surface characteristics and length of useful life. Some such coatings are suitable for decorative purposes. A number of coatings have been developed, one of which is described in U.S. Pat. No. 4,716,083.
U.S. Pat. No. 4,716,083 describes a disordered coating of boron and carbon having the composition B.sub.x C.sub.1-x where "B" represents boron, "C" represents carbon, and "x" and "1-x" represent, respectively, the relative amounts based on atomic weight of boron and carbon present in the coating. The boron and carbon coating is disclosed to be amorphous, polycrystalline and lacking long range order, microcrystalline, or a mixture of any combination of these phases. The coating can be applied by sputtering at relatively low temperatures and produces an adherent, hard coating that is lubricous and can be applied in thin layers.
Despite the favorable characteristics of the coating described in U.S. Pat. No. 4,716,083 as applied to wear parts, tools, and mold surfaces, it is desirable to produce coatings having even more enhanced characteristics, such as hardness, lubricity, and adherence. However, harder coatings sometimes fail to have the advantages of the coating of U.S. Pat. No. 4,716,083. For example, harder, diamond-like coatings have been produced ("DLC" coatings), but these typically do not have sufficient adherence for usefulness on a wear part or tool. DLC coatings frequently fail when a tool or wear part is put to use.